Such access supervision systems are known. They generally supervise access to a pedestrian area, the inside of a building, or a public transportation system, and the obstacle generally consists of a retractable bollard, a gate, or a door.
Access supervision systems must meet two competing requirements. On the one hand, they must provide an effective barrier to the entry of fraudulent users inside the restricted area, but must at the same time provide safety for users while preventing the obstacle, after stowing thereof to free the passage for an authorized user, from colliding with said user upon redeployment.
To meet this dual requirement, the known access supervision systems generally include presence sensors suitable for detecting the presence of a user in the passageway and identifying the position of the user in the passageway. The sensors are most often suitable for identifying fraudulent users who wrongly try to cross the passageway.
However, these systems are not fully satisfactory. In fact, despite the use of presence sensors, a user may not be detected when he is in the passageway, and the obstacle may therefore collide with that user during redeployment. A fraudulent user may also manage to make enough space to cross the passageway by forcing the obstacle.